Cord lock for venetian blinds



July 15, 1947. J. 1.. HUNTER CORD LOCK FOR v ENETIAN BLINDS Filed March 24, 1945 11955. 1;. Has/TEE, INVENTOR.

/ TTOENEX Patented July 15, 1947 2,423,977 I oonn LOOK FOR VENETIAN BLINDS Joseph L. Hunter, Riverside, Califi, assignor to Hunter Engineering 00., Riverside, Calif., a corporation of California Application March 24, 1945, Serial No. 584,655

1 Claim. 1

My invention relates to cord locks for Venetian blinds and has particular reference to a selfoperating locking mechanism for holding the blind raising and lowering cords in any elevated position of adjustment of the blind.

In Venetian blind constructions it is the common practice. to employ a blind structure which includes a plurality of vertically spaced slats suspended upon web ladders, the lower ends of which are secured to a bottom rail structure and the upper ends of which are suspended from suitable tilting 'mechanism located adjacent to or within a head rail structure. To raise and lower the blind it is the usual practice to employ suspending' cords trained over pulleys in the head rail structure, one end of each of the cords bein secured to the bottom rail, the other ends of the cords extending down and being suspended from the head rail adjacent one end thereof where they may be readily grasped by the hand.

In order to hold the blind in any of its elevated positions, various securing devices are employed for fastening the suspended ends of the cords in the position they assume when the blind is in any of its elevated positions. One form of securing device is known as a cord lock comprising a clamping mechanism located upon the head rail and adapted to permit free downward passage of the suspended ends of the supporting cords but resisting upward movement of them, the cord lock being releasable by certain manipulations of the cord ends. I Most of the cord locks which have been heretofore employed are complicated in structure, diflicult to manufacture and to maintain in service, the cord locks after a relatively short period of use tending to permit the cord to slip from the desired adjused positions, either by reason of the wear of the cords or by reason of the wear of the cord engaging clamping devices.

It is therefore an object of my invention to provide a cord lock which is simple and inexpensive to manufacture and install.

Another object of my invention is to provide a cord lock of the character set forth in which th clamping elements are enabled to assume a plurality of clamping positions, in each of which the cord is progressively clamped in a tighter grip.

Another object of my invention i to provide a cord lock of the character described which acts as a combination cord guide and lock, one of the clamping elements comprising a pulley over which the suspended ends of the cords pass.

Another object of my invention is to provide a cord lock of the character described wherein one of the clamping elements comprises a dog pivotally mounted relative to the other clamping member and having a plurality of sets of cord engaging teeth disposed at progressively greater distances from the center about which it pivots to thereby provide progressively greater clamping action as successive sets of teeth are brought into contact with the cord.

Another object of my invention'is to provide a cord lock of the character described wherein swinging of the suspended ends of the cords to different angular relationship to the head rail of I the blind causes a, positive engagement or release of the clamping members.

Other objects and advantages of my invention will be apparent from a study of the following specifications, read in connection with the accompanying drawings, wherein Fig. 1 is a fragmentary perspective view of a portion of a Venetian blind, illustrating my new cord lock in place upon the head rail of such blind;

Fig. 2 is a vertical sectional view through the cord lock shown in Fig. 1 and illustrating the positions of the parts in cord releasing position;

Fig. Bis a vertical sectional view corresponding to Fig. 2 but illustrating the position of the parts in cordlocking position; and

Fig. 4 is a perspective View of the dog clamp illustrated in Figs. 1, 2 and 3.

Referring to the drawings, I have illustrated in Fig. 1 a portion of a Venetian blind comprising a head rail structure I, from which may be suspended the tape ladder, slats and bottom rail (not shown). The conventional cords 2 and 3 employed to support the bottom rail and to raise and lower the blind to any desired position are illustrated as extending horizontally along the head rail I to a position adjacent th end of the head railwhere the cords are trained through a cord lock structure indicated generally at 4, whence the cords extend downwardly and are suspended from that end of the head rail.

The cord -lock 4 comprises a mounting plate 5 bent upon itself toprovide a pair of parallel walls 6 and I enclosing. and housing a pair of clamping elements 8 and 9. The plate is bent rearwardly as indicated at ID to provide a foot piece by which the cord lock may be secured to the head rail I as by means of screws I I.

While I have illustrated the head rail I as comprising a substantially channel-shaped m'etal member having vertical flanges and a bottom web so formed as to enclose and conceal the cord lock structure, it will be apparent that other 

